Reaction plate for friction clutch, in particular for motor vehicles

ABSTRACT

A reaction plate for a friction clutch comprising a cover which includes a mounting insert fixed in the body of the reaction plate. The insert includes, on the outer periphery of the reaction plate, a projecting area for mounting the friction clutch cover.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to reaction plates of mouldable materialfor a friction clutch, especially for motor vehicles.

2. Description of the Prior Art

As is known, such a reaction plate, also known as an engine flywheel,affords a friction surface for engagement with a friction disc furnishedwith friction liners, which may optionally be of divided form, and whichare arranged to be gripped between the said reaction plate and thepressure plate of the clutch.

The pressure plate is subject to the action of axially acting resilientmeans such as a diaphragm or coil springs, which bear on a cover plateadapted to be fixed on the reaction plate, the latter being optionallyof two-part form.

Such a reaction plate, which is typically in the form of a casting, canbe seen for example in the document FR-A-2 463 874 (U.S. Pat. No.4,362,230).

In that document, the cover plate has at its outer periphery a radialflange which is provided with fastening surface portions whereby it issecured to the reaction plate.

This fastening is obtained by means of screws, so that it is necessaryto machine the surface of the reaction plate that faces towards thefastening surface portions of the cover plate, and to form threads inthe latter for the fastening screws.

In a modified version, the cover plate can be secured on the reactionplate by seaming, as is described in the document FR-A-2 526 105 (U.S.Pat. No. 4,600,092).

In that case, it is again necessary to machine the reaction plate inorder that the cover plate can be secured.

In addition, these reaction plates are specific to the cover plate withwhich they are associated.

An object of the present invention is to mitigate these drawbacks in asimple and inexpensive way, and accordingly to reduce the machiningoperations on the reaction plate, while having the option of fasteningthe cover plate in various different ways.

SUMMARY OF THE INVENTION

According to the invention, a reaction plate of the type described aboveis characterised in that it includes a fastening insert anchored in themass of the said reaction plate, being buried within the latter, and inthat the said insert has, projecting in the vicinity of the outerperiphery of the reaction plate, a fastening zone for the fastening ofthe cover plate of the friction clutch.

Thanks to the invention, machining operations on the reaction plate areconsiderably reduced, with the friction surface offered by the reactionplate to the friction disc being machined as in the prior art.

By contrast, the machining operations for fastening of the cover plateare eliminated, due to the presence of the fastening insert. No relativemovement is able to occur between the insert and the reaction plate, dueto the fact that the insert is buried in the reaction plate.

The said insert preferably stiffens the reaction plate because it isembedded in the latter.

Thus the material of the reaction plate can be a less sophisticatedmetal, leading to a reduction in cost.

Because of the insert, it is possible to reduce the thickness of thereaction plate, so giving a reduction in the overall axial size of theclutch, with the insert preferably then extending transversely in thereaction plate.

Where the reaction plate has an axially oriented skirt at its outerperiphery, it is possible to reduce the height of this skirt, andtherefore to obtain the advantage of an increase in the diameter of thefriction surface of the friction disc.

In general terms, because of the inserts, the reaction plate is able torotate at increased rotational velocities, and/or to transmit greatertorques, this plate having enhanced resistance to the effects ofcentrifugal force.

This plate also has enhanced resistance to thermal effects, since itstendency to assume a conical form is reduced due to the presence of theinsert embedded within the reaction plate.

This leads to a reduction in wear of the liners of the friction disc,and possibly to a simplification of the latter.

The reaction plate has no threaded holes for the fastening screws, sothat stress raisers are reduced. The reaction plate is thus of moresound construction.

In addition, excellent fastening of the fastening insert is obtained.

In this connection, the latter is placed in the mould in which thereaction plate is formed, and during the moulding operation, in which,for example, liquid casting metal is poured into the mould, migration ofcarbon atoms takes place so that the fastening insert, which ispreferably of metal, becomes heated.

The fastening insert, embedded in the mass of the reaction plate, isthus in effect welded to the latter. As a result, it is firmly secured.

It will be appreciated that the fastening insert enables the reactionplate to be standardised to an increased extent.

In this connection the insert constitutes an adaptor member.

It is therefore possible to fix the cover plate on the insert, byriveting, screw fastening, welding, adhesive bonding, seaming, clipping,or otherwise.

For example, by giving the fastening member a transverse flange which isdirected radially towards the axis of the assembly, or, in a modifiedversion, away from the axis of the assembly, it is possible to fix thecover plate on the fastening insert by means of screws or rivets, or bywelding or otherwise.

In one embodiment, the fastening zone of the insert extends axially awayfrom the reaction plate.

In this way it is possible to reduce the size of the clutch, within theregion which is typically bounded by a clutch casing, by welding,seaming or clipping the cover plate on the fastening zone of the insert.

Fastening is preferably carried out by welding or alternatively byadhesive bonding in the case where the cover plate is of fibrereinforced plastics material, the cover plate having at its outerperiphery an axially oriented flange which is adapted to cooperate withthe inner periphery (or alternatively with the outer periphery) of thefastening zone of the insert, so that it has a centring function.

It is thus possible to insert the cover plate telescopically into theinsert to a variable extent, so that the inclination and/or the load ofthe diaphragm, which is commonly part of a friction clutch, can therebybe precisely adjusted.

Once the correct inclination or load has been reached, the cover plateis welded or adhesively bonded on the fastening zone of the insert. Itis equally possible to adjust the distance between the diaphragm and thefree end of the engine crankshaft.

Thus, the course of travel of the clutch release bearing, which isadapted in the usual way to work in a traction or thrust mode on theends of the fingers of the diaphragm, as the case may be, can beshortened.

In general terms, manufacturing tolerances can be made less precise, dueto the fact that the cover plate is fitted telescopically on the insert,with intimate contact between these two components.

It is accordingly possible to come very close to the theoreticalcharacteristic curve of the diaphragm.

It will be appreciated that the fastening insert enables the cover plateto be simplified.

In this connection, the cover plate can be flatter than in the priorart, since the fastening insert is an adaptor member which is of benefitto the standardisation of the cover plate.

Thus, the cover plate may have a flat profile at its outer periphery,and be provided with assembly means at its inner periphery for thepivotal mounting of the diaphragm on the cover plate. The machining ofthe cover plate is thereby simplified.

The fastening insert may have holes in its projecting portion, forventilating the clutch. The said insert may also have apertures formounting the pressure plate of the clutch, which is accordingly thenprovided with lugs arranged to cooperate in a complementary manner withthe said apertures.

The pressure plate is thus coupled in rotation to the insert, whilebeing mounted for axial movement with respect to the latter.

The insert facilitates the fitting of a clutch of the twin disc type.

Where the reaction plate has a skirt at its outer periphery, the saidinsert lies inside the said skirt.

The said insert may equally, of course, lie in the transverse portion ofthe reaction plate. All combinations are possible.

The insert is preferably formed with holes, which may be circular,oblong or ovoid, for anchoring it within the reaction plate. The shapeof the holes depends on the application, and in particular on thestresses involved.

In this way the insert is fastened and anchored even more firmly, andincreased torques can be transmitted, since the material of the reactionplate fills the holes. The stiffening of the reaction plate is thusincreased even more, with improved welding of the insert without anyincrease in the thickness of the reaction plate.

It is of course possible to replace the holes with notches formed in theedges of the insert.

In a modified version, the insert may be provided with press formedportions, with the material of the reaction plate penetrating into thehollows of the press formed portions.

The press formed portions are preferably arranged in two groups, withone of the groups being directed in one direction and the other group inthe other direction.

In a modification, the above mentioned alternate press formed portionsmay be replaced by alternate slits.

All combinations are of course possible, the insert having, for example,holes as well as press formed portions.

In all cases, the insert has deformations, formed through it orotherwise, for improving its anchorage in the reaction plate. Thesedeformations thus constitute hooking means.

Because of the insert, it is possible to locate a friction device at theouter periphery of the reaction plate.

In a modified version, the starter crown can be fixed on the insert.

The following description illustrates the invention with reference tothe attached drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of a friction clutch equipped with a damped flywheel inaccordance with the invention, shown in axial cross section taken on theline 1--1 in FIG. 2;

FIG. 2 is a front view, shown partly cut away, of a friction clutchwithout its reaction and pressure plates, and without its friction disc;

FIG. 3 is a view in cross section taken on the line 3--3 in FIG. 2;

FIG. 4 is a view in cross section of part of a friction clutch in asecond embodiment by way of example;

FIG. 5 is a view similar to FIG. 4, but shows a third embodiment by wayof example;

FIG. 6 is a partial sectional view view as seen in the direction of thearrow 6 in FIG. 5;

FIG. 7 is a view similar to FIG. 6, but shows a fourth embodiment by wayof example;

FIG. 8 is a partial sectional view view in axial cross section, showinga fifth embodiment by way of example;

FIG. 9 is a view similar to FIG. 4, but shows a sixth embodiment by wayof example;

FIG. 10 is a partial view showing a clipping lug;

FIG. 11 is a view similar to FIG. 4, but shows a seventh embodiment byway of example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 to 3 show a torsion damping device comprising two coaxial parts1, 2 which are mounted for movement of one with respect to the otheragainst the action of resilient means 8 which are part of a resilientdamping device.

This device is part of a damped flywheel for a motor vehicle.

The first part 1 consists of a plate 11, while the second part 2 againconsists of a plate, 21, which extends parallel to the plate 11. Theplates 11 and 21 are made of a mouldable material, typically in the formof a casting, in order to increase their inertia. In a modification,they may be aluminium based, the choice of material being dependent onthe application.

As a general rule, and in a manner known per se, the molten metal ispoured into a mould.

The two parts 1, 2 thus consist of coaxial masses, one of which rotateswith respect to the other about the axial axis of symmetry X--X of theclutch.

The second mass 2 is mounted for rotation on a tubular hub 14 carried bythe first mass 11. In this example, the hub 14 is integral with theplate 11, though in a modification it may be carried on the latter,while a bearing 15, which is a ball bearing in this example but whichmay, in a variant, be a plain bearing, is interposed between the outerperiphery of the hub 14 and the inner periphery of the plate 21. Thesecond mass 2, which is mounted for rotation on the mass 1 through theinterposed bearing 15, constitutes the reaction plate of a frictionclutch which includes, in the manner known per se, a pressure plate 22,a diaphragm 25 and a cover plate 26.

By contrast with a conventional arrangement (see FIGS. 4, 5 and 9),inwhich an engine flywheel constitutes the reaction plate of the clutch,the flywheel is here divided into two parts in a manner to be explainedbelow.

In accordance with the invention, a reaction plate 21 of mouldablematerial, of the type described above, is characterised in that itincludes a fastening insert 40, 41 which is anchored in the mass of thesaid plate 21, being buried into the latter, and in that the said insert40, 41 has a projecting fastening zone 40 in the vicinity of the outerperiphery of the reaction plate 21, for fastening the cover plate 26 ofthe friction clutch.

In this example the pressure plate 22, typically in the form of acasting, is coupled to the cover plate 26 with axial mobility, in themanner known per se, by means of inclined resilient tongues 27, each ofwhich is fastened at one of its ends to the cover plate, and at itsother end to a lug of the pressure plate 22.

This fastening is obtained by riveting in this example.

The diaphragm 25 is mounted on the cover plate 26 for tiltingdeflection, in this example by virtue of stub pieces 33, one of whichcan be seen in the lower part of FIG. 1. This stub piece has a head withwhich the diaphragm is arranged to engage, and which is aligned with apress formed depression formed in the base of the cover plate.

For more detail, reference should be made to the document FR-A-1 524 350(U.S. Pat. No. 3,499,512).

In a modification, it is possible to use an articulation with two ringswhich are carried by the stub pieces, or arrangements in which washersare carried by lugs projecting from the cover plate and formed bypressing out and bending, as can be seen in FIGS. 4, 5 and 9, to bedescribed later herein.

The diaphragm 25 bears on the base of the cover plate 26 in order tourge the pressure plate 22 towards the reaction plate 21. The frictionclutch further includes a friction disc 23 connected to a central hub24, which is mounted in rotation on the input shaft (not shown) of thegearbox by means of a splined coupling.

It will be recalled that the assembly of the components 26, 25, 24, 27constitutes a unitary clutch mechanism, this being seamed by means ofits dished cover plate on to the reaction plate 21, by virtue of theinserts 40, 41 in accordance with the invention.

The friction liners which are carried by the disc 23 at its outerperiphery are normally gripped under the action of the diaphragm betweenthe plates 21, 22, so that the clutch is normally engaged.

In order to declutch, the clutch being of the push to release type inthis example, it is necessary to exert a thrust on the ends of thefingers of the diaphragm 25 by means of a clutch release bearing 28,thus disengaging the clutch.

To this end, the release bearing 28 is mounted for axial movement alonga tube guide 30 which is fixed to the gearbox 31, and through which theinput shaft of the latter extends.

The said release bearing 28 is controlled by a declutching fork 29 whichcauses it to be displaced axially to the left in FIG. 1, thus causingthe diaphragm to be deflected in a tilting movement, several positionsof which are shown in FIG. 1.

The first rotating mass 11 is arranged to be connected, through itsinner periphery, in this example by means of screws 32, to a drivingshaft which is here the crankshaft 34 of the internal combustion engineof the motor vehicle, while the second rotating mass 2 is coupled inrotation, through the clutch mechanism 22, 25, 26, 27 and the disc 23,to a driven shaft, which in this case is the input shaft of the gearboxof the vehicle.

The first mass 1 in the form of a plate consists essentially of acentral portion 11, oriented transversely and being in the form of aplate or wheel disc, which is extended at its outer periphery by anintegral, axially oriented, cylindrical skirt portion 12.

The said mass 1 carries at its outer periphery a starter crown 13 whichis arranged to be driven by the pinion of a starter (not shown).

The inner portion of the mass 1 is provided with a plurality of holes,through which pass the screws 32 that fasten the mass 1 to thecrankshaft 34.

It will be noted that the reaction plate 21 has corresponding holeswhich enable a tool to be passed through them for tightening the screws32, and that the bearing 15 is of a reduced size, being located radiallyinwards of the said holes.

In this example, the insert 40, 41 is of metal plate and is pressformed.

This insert has a transverse portion 41, which is embedded, and thusanchored firmly, in the transverse main portion of the reaction plate21.

This portion 41 if formed with a plurality of holes 44 in order toimprove the anchorage.

At its outer periphery, the said portion 41 is extended towards the baseof the cover plate 26 by an axially oriented cylindrical portion 40,which may be divided into lugs and which constitutes the fastening zonein accordance with the invention. The portion 40 projects axially withrespect to the friction surface of the reaction plate, and extendsradially outwards beyond the outer periphery of the plate 21 (in thevicinity of the latter), and is therefore spaced away from the frictionliners of the disc 23 and from the pressure plate 22 which theysurround. The friction surface which is offered by the plate 21 to thefriction liners of the disc 23 can thus extend as far as the outer edgeof the plate 21. The cover plate 26 has at its outer periphery anaxially oriented flange 35, which is of divided form in this embodimentin order to facilitate fitting.

The flange 35 is cylindrical, and is arranged to cooperate in slidingengagement with the inner periphery of the portion 40, which constitutesa centring element. The flange 35 is therefore in intimate contact withthe portion 40.

The flange 35 is thus interposed between the portion 40 and the outerperiphery of the pressure plate 22.

It is therefore possible to engage the cover plate 26, which in thisexample is of press formed sheet metal, within the portion 40 by avariable amount.

It is of course possible to reverse the structure, with the flange thensurrounding the portion 40, cooperating with the outer periphery of thelatter. In all cases, the portion 40 constitutes a guiding and centringelement for the flange 35, and therefore for the cover plate 26.

In this way, the inclination and/or the load of the diaphragm 25 is ableto be precisely controlled with respect to a datum, which is here thecrankshaft 34 of the engine of the vehicle.

Once the diaphragm has attained the desired inclination or load,fastening of the cover plate is carried out, in this example on the freeend of the fastening zone 40 of the insert, this fastening beingobtained here by welding to give a band 43 of weld metal.

Once the flange 35 embraces the portion 40, the welding operation iscarried out along the free edge of the flange.

In the present example, the resilient means of the resilient dampingdevice comprise at least one resilient member 8, and are interposedgenerally radially between the plates 11 and 21.

In the present case, resilient members are mounted in at least onearticulated cassette 10 (FIGS. 2 and 3), which comprises, firstly, adamper plate 3 formed with first housings 82 for mounting of theresilient members 8 therein, and secondly, two guide members 4, 5disposed on either side of the said damper plate and having, in facingrelationship with the first housing 82, second housings 81 for mountingthe said resilient members 8, which consist in this example of two coilsprings, and which may optionally be mounted in the housings 81, 82 inpairs, parallel to each other.

It is of course possible, in a modified version, to arrange a singlespring in each cassette, and therefore to provide a single pair ofhousings 81 and a single housing 82.

The guide members 4, 5 are fixed to each other laterally. The damperplate 3 and the guide members 4, 5 are mounted in a head to toeconfiguration, with the said damper plate having, at one of its outerand inner peripheries, a first projecting element 72 for mounting afirst articulating means 6 on a first one of the said masses 11, 12,while the guide members 4, 5 have, at their outer or inner periphery, asecond projecting element 71, in facing relationship with each other,for mounting a second articulating means 7 on the other one of the saidmasses.

The said second projecting elements 71 and first projecting elements 72are offset radially from each other, just like the articulating means 6,7.

In this example, the first housings 82 and second housings 81 consist ofradially oriented windows, with the second housings 81 being formed withlips.

In a modification, the first housing may consist of a radially orientedslot which is open radially on the opposite side from the firstprojecting element.

In a modification, the second housings 81 may consist of press-formeddepressions.

In every case, however, the guide members 4, 5 have flanges 90, 91 attheir outer periphery for fastening them together, in this example withthe aid of rivets 92.

The said guide members 4, 5 are thus fixed laterally to each other byriveting.

In a modification, they may be fixed to each other, in their flanges, bywelding or by clipping.

In this example, two springs 8 are mounted parallel to each other withinthe said cassette, and the damper plate 3 is articulated at its innerperiphery on the plate 21, while the guide members 4, 5 are articulatedat their outer periphery on the plate 11. Each of the members 4, 5 has,adjacent to the first projecting element 72, a notch 73 which issemicircular in this example, so that a pivot pin 6, to be describedlater herein, can extend through it, which enables the springs 8 to beincreased in length.

The same is true for the damper plate 3, which has, adjacent to theprojecting element 71, a notch 74 which is semicircular in this example,so that a pivot pin 7, to be described later herein, can extend throughit.

Accordingly, the springs 8 are of maximised length.

More precisely, the damper plate 3 is articulated on the plate 21 (atthe inner periphery of the latter) by means of a pivot pin 6 having ashouldered head which is fixed, in this example by force fitting, on theplate 21, and which is surrounded by a needle bearing, which isinterposed between the said pivot pin and a bush which is fixed on thedamper plate 3.

In a modification, a plain bearing may be used.

The said bush extends axially between the plates 11 and 21, beingsecured to the damper plate 3 by welding in the present case.

The members 4, 5 are articulated at their outer periphery on the plate11 by means of a pivot pin 7, which is force fitted into the plate 11and into a member 60, at the outer periphery of the plate 21.

The pivot pin 7 is surrounded by a needle bearing interposed between thesaid pivot pin and a sleeve which is fixed, in this example by welding,to the guide members 3, 4 sic!.

The sleeve and the needle bearing are interposed axially between theplate 11 and the member 60, which is formed with a chimney portion forreceiving the pivot pin 7.

In a modification, the sleeve may be carried on the members 4, 5 bybeing seamed on to them. To this end, the sleeve has a central portionof enlarged diameter, extending between the two members 4, 5 andoffering a shoulder to these latter. The ends of the sleeve are upset soas to fasten it, by seaming, to the members 4, 5.

The plate 11 is formed with an aperture 16 opposite to a cassette 10.

In this example, four articulated cassettes 10 and four pivot pins 6, 7,spaced apart at regular intervals, are provided as shown in FIG. 2. Thisnumber does of course depend on the application.

The member 60 is fastened by riveting to the outer periphery of theplate 11, and more precisely on the portion 12 of the latter.

The said member 60, which is of metal plate in this example, then servesto stiffen the plate 11 which is perforated by the through apertures 16,the inner edges of which are in the form of an arc of a circle.

It also, with the plate 11, defines a support in which the pivot pins 7are mounted.

The member 60 has at its outer periphery an axially oriented flangeformed with slots 61 which constitute mortices, and with lugs 62 at itsfree end. The lugs 62 are bent back radially towards the axis of theassembly.

The member 60 is accordingly shaped in the form of a comb before thelugs 62 are bent back.

Situated between the outer periphery of the transverse portion of themember 60 and the lugs 62, there are, in axial succession, a frictionring 51, an application ring 52, an axially acting resilient ring 53which is a Belleville ring in this example, but which may in a modifiedversion be a corrugated ring, and finally an abutment member 54 incontact with the lugs 62.

The application ring 52 has at its outer periphery lugs which constitutetenons, and which are engaged in the slots 61 of the member 60. The ring52 is thus coupled in rotation, optionally with a clearance, with themember 60 through a coupling of the tenon and mortice type.

The member 51 is made of a friction material, which in this example is aplastics material, and has a cross section which is generally in theform of an inverted L.

The member 51 has, at its inner periphery, local bosses 63 which areengaged, with or without a circumferential clearance, in local recesses45 press formed in the junction zone where the fastening zone 40 joinsthe anchor zone 41 of the fastening insert 40, 41.

The recesses 45 are directed towards the axis of the assembly, being incontact with the outer periphery of the reaction plate 2. For thisreason the bosses 63 are chamfered.

Thus, by virtue of the fastening insert 40, 41, a hysteresis device 50is provided which works between the member 40, 41 and the member 60, thesaid device comprising, firstly, the rings 52, 53, 54 which are mountedin rotation on the member 60 through the member 52, and secondly, thefriction member 51 which is mounted in rotation, optionally with aclearance, on the member 40 and therefore on the plate 21. The device 50thus constitutes a friction device acting between the two masses 1, 2,while making the best use of the available space without interferingwith the clutch casing.

Thus, during the relative movement between the two masses 1, 2, thesprings 8, and therefore the cassettes 10, become inclined as is shownin the upper part of FIG. 2, with relative movement between the members51 and 60. The springs 8 are compressed during this relative movement.

The two concentric masses 1, 2 are, in this way, mounted for movement ofone with respect to the other against the action of radially actingresilient means 8 and of axially acting friction means 50.

It will also be noted that two friction pads 9 are interposedoperatively between the lateral edges of the damper plate 3 and thelateral edges of the guide members 4, 5.

These pads 9 include bosses which are engaged in slots formed in thelateral edges of the damper plate 3. The pads 9 overlie the edge of thedamper plate 3.

Thus, there is an additional friction effect during the relativemovement between the two masses 1, 2, with the pads guiding the damperplate 3 during its relative movement with respect to the members 4, 5.In this way any risk of jamming is avoided.

It will be noted that the insert 40, 41 thus has a transversely orientedanchor zone 41 which is buried in the plate 21, together with an axiallyoriented fastening zone 40, so providing a device both for friction andfor fastening the cover plate 26, in this example in a controllablemanner.

The engine flywheel may of course be all in one piece. Thus, in FIG. 4the reaction plate 21 is arranged to be secured directly on to thecrankshaft of the engine.

This plate 21 then carries the starter crown 13.

In FIG. 4, the disc 23 is of the elastic type, and carries, in a wayknown per se, and as can be seen in FIG. 1 of the document FR-A-2 463874, two guide rings which are disposed on either side of a damper platefixed to the hub 24.

Circumferentially acting resilient means (not shown) are interposedoperatively between the damper plate and the two guide rings, so as tocouple them together resiliently.

The guide rings are coupled together by the spacer bars which extendthrough apertures formed for this purpose in the damper plate.

The resilient means, which consist in practice of coil springs, aremounted in windows formed in facing relationship with each other in thedamper plate and in the guide rings.

The spacer bars enable the disc that carries the friction liners to beassembled with the guide rings.

These friction liners are arranged to be gripped between the pressureplate 22 and the reaction plate 21.

As in FIG. 1, the diaphragm 25 bears at the outer periphery of itsBelleville ring on a boss which projects axially from the pressure plate22, while at the inner periphery of its Belleville ring it is mountedbetween a primary abutment and a secondary abutment.

These abutments are part of the means 133 which apply the diaphragmpivotally to the cover plate 126.

The said means 133 comprise lugs which, in this example, projectintegrally from the cover plate 126, being formed by bending and pressforming. These lugs extend through openings which are formed in thediaphragm at the root of its fingers, and their ends are bent radiallyaway from the axis of the assembly.

A frusto-conical ring and an application ring are interposed between thebent back ends of the said lugs and the said diaphragm.

The frusto-conical ring affords a secondary abutment for the diaphragm25, facing a primary abutment which is press formed in the cover plate126.

Because of the insert in accordance with the invention, the cover plate126 can be made in a simple form, being reduced to an annular platewhich has the assembly means 133 at its inner periphery.

This plate 126, which is of metal in this example, is fixed, in thepresent case by means of a band of weld metal 143, to the fastening zone140 of the metallic insert.

The cover plate is fixed to the free end of the fastening zone 140.

As before, it is possible to obtain precise regulation of theinclination and/or the load of the diaphragm 25, by causing the coverplate 126 to penetrate to a greater or lesser extent into the zone 140,which is in the form of a crown.

In this example, the insert is oriented axially and is in the form of atube. It is anchored in the annular skirt which is carried by thereaction plate 21 at its outer periphery.

The insert 140 has holes 144 whereby it is anchored firmly in the plate21.

These holes are filled with the material of the plate 21, and in thisexample they are oblong, though in a modification they may be circular.

The insert thus has an anchor zone embedded within the mass of the plate21, radially outwards of the friction surface offered by the pressureplate 1 to the friction disc 23, together with an axially projectingzone 141 at the outer periphery of the plate 21. This zone extendstowards the cover plate.

The zone 141 may optionally be divided into fingers.

It will be noted that overall size is reduced in this region. In thisconnection, part of the casing 147 of the clutch can be seen in thelower part of FIG. 4. This casing is very close to the free end of theskirt of the plate 21, so that it is difficult to fasten the cover plateto the skirt at this location by screw fastening, as the screws wouldrun the risk of interfering with the said casing.

The use of welding in accordance with the invention not only enables thecover plate to be fastened, but also enables the overall size to bereduced.

The cover plate can of course be provided with a radial fastening flangeat its outer periphery.

Thus in FIGS. 5 and 6, the cover plate 226 has holes 227 at its outerperiphery.

These holes are so arranged that shouldered lugs 245, which are part ofthe free end of the fastening zone of the metallic insert 240 buriedwithin the mass of the skirt of the plate 21, extend through them as inFIG. 4.

The radial fastening flange of the cover plate thus makes abuttingengagement against the shoulder of the lugs 245.

In this example, the shoulder is defined by the free end of the insert240, with the lugs 245 projecting axially with respect to the said freeend. The lugs 245 may of course be narrower at their free end than intheir anchor zone by which they are anchored to the insert, therebydefining shoulders.

The free ends of the lugs 245 are adapted so that, after having passedthrough the holes 227, they are upset so as to secure the cover plateand the zone 240 together.

The cover plate 226 is thus secured to the fastening insert 240 byseaming.

The structures can of course be reversed.

Thus, in FIG. 7, the cover plate has at its outer periphery transverselyoriented lugs 345, which are engaged in through openings 427 formed inthe fastening zone 340 of the metallic insert at its free end.

After the lugs 345 have been inserted into the openings 427, thematerial of the lateral edges of the opening 427 are upset, leading tothe cover plate being secured to the insert 340 by seaming, with thesaid edges undergoing plastic flow at 346.

The insert 440 may of course have a free end which is offset radiallyoutwards with respect to the main portion of its fastening zone. Thisoffset is defined in a rounded junction zone.

Having regard to this offset, it is possible (FIG. 8) to form, throughboth the free end of the fastening zone 440 and the main portion of thezone 440, apertures 450.

Thus, the pressure plate 22 may have at its outer periphery axiallyoriented lugs 122 which are engaged, in the manner of tenons, in theapertures 450 which constitute mortices. These lugs 121 pass below thefree end of the portion 440.

The cover plate is of course then fixed to the free end of the zone 440,either as in FIG. 7, or, in a modification, by welding.

Thus, thanks to the invention, the pressure plate 22 can be coupled inrotation to the reaction plate 21, while being mounted for axialmovement with respect to the latter.

It is therefore possible, thanks to the invention, to omit the tongues27 of FIG. 1.

It is of course possible to retain the lugs 27 of FIG. 1 and to make useof them for the assembly of a twin-disc clutch using the insert 440.

This clutch comprises two friction discs and two pressure plates, one ofwhich is coupled in rotation, with axial mobility, by the tenons 122,while the other plate is coupled in rotation to the cover plate by thetangential tongues.

It can be seen, by reference to the document FR-A-2 628 492 (U.S. Pat.No. 4,892,177), that the arrangement in accordance with the inventionenables a twin-disc clutch to be easily made with the aid of the insertsaccording to the invention.

The axially oriented fastening zone of the metallic insert can of coursebe formed with holes for ventilating the clutch.

The cover plate can of course be fastened by being clipped to theinserts 540 (FIG. 9). In this case the metallic inserts 540 have attheir free ends shouldered lugs 541 which extend through a complementaryassociated aperture formed in the flange of the cover plate. Afterhaving passed through the apertures, the lugs are bent back towards theaxis of the assembly, or, in a modification, away from the axis of theassembly.

In FIG. 1, the two masses may of course be mounted for movement of onewith respect to the other, against the action of circumferentiallyacting resilient means.

Thus in FIG. 11, the insert 640, anchored in the peripheral skirt 121 ofthe reaction plate 21 with the aid of holes 144 as in FIGS. 4 and 5, isextended on the face opposed to the reaction plate, that is to saytowards the plate 11.

The metallic insert hugs the profile of the reaction plate 21, which isreduced in thickness and inclined at this location. It stiffens theplate 22.

The free end of the said insert is bent radially outwards so as to formradial lugs 646, which afford an abutment for the circumferential endsof the circumferentially acting resilient members 116, which are mountedin pairs.

These springs 116, which in this example are in the form of pre-curvedcoil springs mounted in pairs, also bear on members 114 which are fixedto the plate 11. More precisely, this plate 11 has, from place to place,abutment members 114 which are secured by riveting to the plate 11,together with abutment members 113 which are fixed, in this example byscrew fastening, to the free end of the skirt 112 formed on the plate atits outer periphery.

In this example, the plate 11 generally surrounds the reaction plate 21.This plate 11 is relieved for mounting the springs 116 and members 114,113, together with the insert 140. The double flywheel therefore has areduced axial size.

It is possible to provide a sealed chamber, filled for example withgrease and containing the circumferentially acting springs 116. It ismerely necessary to provide a sealing ring between the skirt 121 and themember 113, and between the plates 11, 21 radially inwards of thesprings, which are thereby lubricated so as to reduce wear.

All combinations are of course possible. Thus, the insert of FIG. 4 maybe extended by a transverse portion extending into the transverseportion of the reaction plate 21.

The cover plate 126 may be fitted by clipping or seaming on the inserts240, 540 respectively.

As will be understood, and as will appear from the description, it ispossible to extend the fastening zone of the insert radially inwardly oroutwardly, so as to form a transverse portion whereby the cover platecan be secured by screw fastening, riveting, welding, or otherwise.

With an insert having a transverse flange, it is thus possible to fitcover plates and pressure plates of different sizes on a given reactionplate.

The clutch may of course be of the pull to release type, as described inthe document FR-A-2 463 874 (U.S. Pat. No. 4,362,230).

The cover plate may be made of plastics material reinforced with fibres,for example glass fibres.

In a modified version of FIG. 1, the portion 40 may lie in contact withthe outer periphery of the plate 21, with the flange 35 then surroundingthe portion 40 in the way described earlier herein. It then becomespossible to fix the starter crown 13 on the portion 40, especially whenthe reaction plate is fixed directly on the crankshaft 34. In each case(FIG. 1 and the modified version), the friction surface of the reactionplate is able to extend as far as the outer edge of the reaction plate.The same is true for the friction liners of the friction disc.

In a modified version, the stub pieces 33 and the diaphragm 25 can bemounted outside the cover plate, as in FIG. 4 of the document FR-A-1 524350.

In that case, the bosses provided on the pressure plate 22 forengagement by the diaphragm 25 extend through the cover plate, which isfixed on the insert, for example as in FIG. 7, by welding.

It will be appreciated that the rolling bearing 15 is of reduced size,and that it lies radially inwards of the screws 32, which enables thesprings 8, and therefore the cassettes 10, to be increased in length.

In the drawings, in the rest position of the damped flywheel, thecassettes 10 extend radially, so that the articulating means 6, 7 arealigned on a common axis.

In a modified version, in the said rest position the cassettes 10 may beslightly inclined, with the articulating means 6, 7 then being offsetcircumferentially.

It is of course possible to reverse the structures, with the members 4,5 being articulated at their inner periphery on the reaction plate 21,while the damper plate 3 is then articulated at its outer periphery onthe plate 11, with the member 60 being interposed.

The closed holes 44 may be replaced with press formed portions, or withslits, or with lugs, preferably alternated with each other.

For example, in FIG. 1 the anchor portion 41 would then preferably havea first set of press formed portions directed towards the plate 11, anda second set of press formed portions directed axially towards the plate22. It is of course equally possible to provide holes.

In FIG. 4, the press formed portions would be directed radially towardsthe axis and radially away from the axis.

The holes may be replaced by open cut-outs formed in the edges of theinsert.

In all cases, the insert is provided with deformations, which are eitheropen (in the sense that the holes, the cut-outs, the slits and the lugsare open), or not open (i.e. the press formed portions), or both atonce, for enlarging its anchorage in the mass of the reaction plate.

It will be noted that in FIGS. 4, 5, 9, the holes are formed in a pressformed zone. The insert may of course carry pivot pins or the like,attached on the latter, for example by seaming. An improved anchorage isthus obtained. The insert accordingly has the benefit of hooking meansin the form of deformations, pins etc.

As will be understood from the foregoing, the apertures 16 enable anyinterference between the cassettes 10 and the plate 11 to be avoided.

The said apertures 16 are accordingly disengagement apertures, whichenable the axial size of the damped flywheel to be reduced, and whichassist ventilation.

Finally, the insert may optionally be of a divided form. However, itdoes preferably include a continuous annular portion.

It is of course possible, for example in FIG. 1, to divide the innerperiphery of the transverse portion into lugs.

Similarly, in FIGS. 4, 5, 9 the ends of the inserts may be divided intolugs.

In the drawings, the cover plate is press formed from metal plate. In amodified version, the cover plate can of course be made of a mouldablematerial, for example as a casting or of an aluminium based material orfibre reinforced plastics material. The fastening zone of the insert maybe long in the axial direction, with its length being determinedaccording to the application.

We claim:
 1. A reaction plate having a mass of moldable material for afriction clutch having a cover plate (26, 126, 226), in which saidreaction plate has a transverse main portion, including a fasteninginsert (40, 41 - 140 - 240 - 340 - 440 - 540 - 640) having a transverseoriented anchor zone anchored in the mass of the reaction plate (21) andbeing embedded therein thereby preventing all relative movement betweensaid fastening insert and said reaction plate, said insert has,projecting in the vicinity of the outer periphery of the reaction plate21, a fastening zone (40, 140, 240, 340, 440, 540, 640) extendingaxially away from the reaction plate (21) for the fastening of the coverplate (26) of the friction clutch, wherein the fastening insert (40,41 - 140 - 240 - 340 - 440 - 540 - 640) has deformations (44, 144) forenhancing its anchorage in the reaction plate.
 2. A plate according toclaim 1, wherein the insert (40, 41 - 140 - 240 - 340 - 440 - 540 - 640)has holes (144) for anchoring it in the reaction plate (21).
 3. A plateaccording to claim 1, wherein the insert (40, 41 - 140 - 240 - 340 -440 - 540 - 640) includes an anchor zone extending transversely in atransverse main portion of the reaction plate (21).
 4. A plate accordingto claim 1, in which said reaction plate has a skirt at its outerperiphery, wherein said insert is embedded into said skirt.
 5. A plateaccording to claim 1, wherein the fastening zone has a transverselyoriented flange at its free end.
 6. A plate according to claim 1,wherein a cover plate is secured by welding on the fastening zone of theinserts (40, 41 - 140 - 240 - 340 - 440 - 540 - 640).
 7. A plateaccording to claim 1, wherein the fastening zone (240) has shoulderedlugs (245) for securing the cover plate (226) by seaming on thefastening zone (240).
 8. A plate according to claim 1, wherein, thefastening zone (540) has shouldered lugs for securing the cover plate byclipping on to the fastening zone.
 9. A plate according to claim 1,being part of an engine flywheel comprising two masses (1, 2) which aremounted for movement of one with respect to the other against the actionof circumferentially acting resilient members, wherein the said insert(640) is extended in length so as to project on another surface of thereaction plate (21) and to offer lugs (646) for engagement with theresilient members (116).
 10. The plate according to claim 1, whereinsaid deformations are defined by holes extending through said transverseoriented anchor zone, said reaction plate being molded about saidtransverse oriented anchor zone and through said holes.
 11. The plateaccording to claim 1, wherein said reaction plate comprises a centralaxis and said transverse oriented anchor zone extends within saidreaction plate perpendicular to said central axis.
 12. A reaction platehaving a mass of moldable material for a friction clutch having a coverplate (26, 126, 226). in which said reaction plate has a transverse mainportion, including a fastening insert (40, 41 - 140 - 240 - 340 - 440 -540 - 640) having an anchor zone anchored in the mass of the reactionplate (21), being embedded within the latter, and in that said inserthas, protecting in the vicinity of the outer periphery of the reactionplate 21, a fastening zone (40, 140, 240, 340, 440, 540, 640) extendingaxially away from the reaction plate (21) for the fastening of the coverplate (26) of the friction clutch, wherein, a cover plate is secured bywelding on the fastening zone of the inserts (40, 41 - 140 - 240 - 340-440 - 540 - 640) and the cover plate has at its outer periphery anaxially oriented flange (35) which is engaged in an internal bore of anannular fastening zone (40) of the insert (40, 41).
 13. A plateaccording to claim 12, wherein the cover plate is secured, by weldingthrough its flange (35), on a free end of the fastening zone (40).
 14. Areaction plate having a mass of moldable material for a friction clutchhaving a cover plate (26, 126, 226), in which said reaction plate has atransverse main portion, including a fastening insert (40, 41 - 140 -240 - 340 - 440 - 540 - 640) having an anchor zone anchored in the massof the reaction plate (21), being embedded within the latter, and inthat said insert has. projecting in the vicinity of the outer peripheryof the reaction plate 21, a fastening zone (40, 140, 240, 340, 440, 540,640) extending axially away from the reaction plate (21) for thefastening of the cover plate (26) of the friction clutch. wherein, saidplate is part of an engine flywheel comprising two masses (1,2) whichare mounted for movement of one with respect to the other against theaction of resilient members (8), wherein, the fastening zone (40) of theinsert has local press formed portions (45) for mounting a friction ring(51) which is part of a hysteresis device (50) interposed operativelybetween the two masses (1,2) of the engine flywheel.
 15. A reactionplate having a central axis formed of a mass of moldable material for afriction clutch having a cover plate, said reaction plate comprising:atransverse main portion extending substantially perpendicular to saidcentral axis; a fastening insert havinga transverse oriented anchorzone, said anchor zone extending substantially perpendicular to saidcentral axis and embedded within said transverse main portion of saidreaction plate, and a fastening zone extending axially away from saidreaction plate for fastening to said cover plate of said frictionclutch, wherein said reaction plate is molded about said transverseoriented anchor zone and thereby disposed directly adjacent to andcircumscribing an outer peripheral surface of said transverse orientedanchor zone to prevent relative movement between said fastening insertand said reaction plate.